The multimedia consumer electronics market is rapidly evolving with increasingly sophisticated audio/video products. Consumers are becoming accustomed to high definition video in their home entertainment centers as well as high end graphic capabilities on personal computers. Several audio/video interface standards have been developed to link a digital audio/video source, such as a set-top box, DVD player, audio/video receiver, digital camera, game console or personal computer with an audio/video rendering device such as a digital television, a high definition video display panel or computer monitor. Examples of digital video interface technology available for consumer electronics comprise High-Definition Multimedia Interface (HDMI), Display Port, Digital Video Interface (DVI) and Unified Display Interface (UDI) for example. These audio/video interfaces may each comprise unique physical interfaces and communication protocols.
As high data rates are required, new transmission technologies enable higher transmission rates over copper cabling infrastructures. Various efforts exist in this regard, including technologies that enable transmission rates that may even reach 100 Gigabit-per-second (Gbps) data rates over existing cabling. For example, the IEEE 802.3 standard defines the (Medium Access Control) MAC interface and physical layer (PHY) for Ethernet connections at 10 Mbps, 100 Mbps, 1 Gbps, and 10 Gbps data rates over twisted-pair copper cabling 100 m in length. With each 10× rate increase more sophisticated signal processing is required to maintain the 100 m standard cable range. Non-standard transmission rates comprise 2.5 Gbps as well as 5 Gbps.
The specification for 10 Gigabit-per-second (Gbps) Ethernet transmissions over twisted-pair cabling (10GBASE-T) is intended to enable 10 Gbps connections over twisted-pair cabling at distances of up to 182 feet for existing cabling, and at distances of up to 330 feet for new cabling, for example. To achieve full-duplex transmission at 10 Gbps over four-pair twisted-pair copper cabling, elaborate digital signal processing techniques are needed to remove or reduce the effects of severe frequency-dependent signal attenuation, signal reflections, near-end and far-end crosstalk between the four pairs, and external signals coupled into the four pairs either from adjacent transmission links or other external noise sources. New IEEE cabling specifications are being considered for 40 Gbps and 100 Gbps rates.
There may be instances where the data rate required for transmission in one direction may be much higher than the data rate required for transmission in the opposite direction, such as the delivery of interactive video from a central office to the consumer, for example. In this regard, the data rate for the transmission of video in one direction may be much higher than the data rate required for transmitting interactive commands in the opposite direction.
A/V Bridging (AVB) comprises a set of specifications, which define service classes (or AVB services) that enable the transport of audio/video (A/V) streams (and/or multimedia streams) across an AVB-enabled network (or AVB network) based on selected quality of service (QoS) descriptors. Specifications, which enable the definition of AVB service classes, include the following.
A specification, which enables a set of AVB-enabled devices (or AVB devices) within an AVB network to exchange timing information. The exchange of timing information enables the devices to synchronize timing to a common system clock, which may be provided by a selected one of the AVB devices within the AVB network.
A specification, which enables an AVB destination device to register a request for delivery of a specified AV stream from an AVB source device. In addition, an AVB source device may request reservation of network resource, which enables the transmission of a specified AV stream. The Stream Reservation Protocol (SRP) defined within the specification provides a mechanism by which the AVB source device may register the request to reserve resources within the AVB network (such as bandwidth) to enable the transmission of the specified AV stream. The Multiple Multicast Registration Protocol (MMRP) may enable an AVB destination device to register the request for delivery of a specified AV stream.
A specification, which defines procedures by which AV streams are transported across the AVB network. These procedures may include methods for the queuing and/or forwarding of the AV streams by individual AVB devices within the AVB network.
A typical AVB network comprises a set of AVB devices, which are collectively referred to as an AVB block. An AVB network may comprise wired local area networks (LANs) and/or wireless LANs (WLANs), for example. Individual AVB devices within the AVB network may include AVB-enabled endpoint computing devices (such as laptop computers and WLAN stations), AVB-enabled switching devices (AV switches) within LANs and AVB-enabled access points (APs) within WLANs, for example. Within the AVB block, AV destination devices may request AV streams from AV source devices, which may be transported across the AVB network within specified latency target values as determined from the QoS descriptors associated with delivery of the AV stream.
Further limitations and disadvantages of conventional and traditional approaches will become apparent to one of skill in the art, through comparison of such systems with the present invention as set forth in the remainder of the present application with reference to the drawings.